2006 honda civic, Immobilizer System activated?

while out of town, I left the inside (dome) light on. when I returned home 2-3 days later the battery was COMPLETELY drained. I charged the battery, but now itsactivated the Immobilizer System. (green key on dashboard) blinks. Car will start but only runs 3-5 seconds and shuts down. Never had any problems before. Honda dealership wants me to let them toe it in for 95.00, then they'll look at it.I go the code for the radio & it works fine now. Anybody know a way to get out of taking to the dealer. I dont have much money and it just went out of warranty. I'm sure they're going to stuck to me. Thanks